1. Field of the Invention
The present invention relates to a clamping member for clamping a cutting insert on a tool holder, a tool holder provided with the clamping member, and an indexable cutting tool which has a cutting insert mounted on the tool holder.
2. Description of the Related Art
A throw away cutting tool that has a cutting insert removably fixed on the top end surface of the distal end portion of a tool holder has been known. Japanese Patent Laid-Open No. H10-071508(1998) discloses a mechanism for mounting a cutting insert on a tool holder by pressing the cutting insert placed on an insert mounting seat, which is formed on the top end surface of the distal end portion of the tool holder, against the bottom surface and the wall surface of the insert mounting seat with a clamping piece (a clamping member) from the above of the cutting insert. In the mounting mechanism, the clamping member has a sliding surface mutually contacting with an inclined surface of the cutting holder and a pressing portion formed with a protrusion engaging with a mounting hole, which is formed in the cutting insert. When pressing the clamping member with a clamping bolt, the protrusion is inserted into the mounting hole of the insert, as the clamping member is moved down, and the sliding surface of the clamping member is mutually engaged with the inclined surface of the tool holder, so that the clamping member moves in a direction along with the inclined surface with respect to the tool holder. As a result, the clamping member presses the cutting insert both toward the bottom surface and the wall surface.
In the above type of cutting insert, as the clamping bolt is tightened, a moment which rotates the clamping member about a center axis of the clamping bolt acts thereon associated with the rotation of the clamping member. Because of this, the tightening of the clamping bolt possibly causes the protrusion of the rotated clamping member to be misaligned with the mounting hole of the cutting insert. Consequently, the protrusion might not be inserted into the mounting hole so that the cutting insert might not be securely clamped on the insert mounting seat.
It is an object of the present invention is to provide a clamping member being preferable to clamp a cutting insert on a tool holder, a tool holder provided with the clamping member and an indexable cutting tool in which a cutting insert is mounted on the tool holder, for solving the above problem.